What You Should Know About Methylene Blue

Methemoglobinemia, Explained

Methemoglobin is a type of hemoglobin that cannot carry oxygen correctly to the body's tissues2. People with this condition might experience the following symptoms:

• Fatigue
• Dizziness
• Headache
• Nausea
• Vomiting
• Shortness of breath
• Rapid heartbeat
• Loss of muscle coordination
• Blue-colored skin

Methemoglobinemia can be inherited or the result of an injury. Other causes include exposure to certain drugs, foods, and chemicals. Methemoglobinemia can affect patients at any age.

How Can Methylene Blue Help?

Healthcare providers might treat methemoglobinemia with the medication methylene blue. It is a positively charged dye that draws to positively acidic cell components in the body (like the cell nucleus) and a photosensitive compound that releases singlet oxygen when exposed to ambient light3.

In hospital environments, healthcare providers can inject low doses of methylene blue into a patient's vein. After being injected, the body's metabolism breaks down the medication into leukomethylene blue—a reducing agent that lowers methemoglobin levels in the patient's bloodstream3.

Before injecting methylene blue into the body, healthcare providers will ask patients if they have any of the existing conditions1, which can affect the efficacy of treatment:

• Cyanide poisoning
• Kidney disease
• Glucose-6-phosphate dehydrogenase (G6PD) deficiency
• Any known allergic reactions to methylene blue, thiazide diuretics, phenothiazines, and other medicines.
• Any known allergic reactions to dyes, foods, or preservatives

Patients who are pregnant, trying to get pregnant, or breastfeeding might not be suitable for this treatment.

Is Methylene Blue Safe?

Research shows that methylene blue is safe in therapeutic doses of <2mg/kg4. The medicine can cause toxicity in high doses4. As healthcare providers can only administer methylene blue in hospital settings, patients can avoid any dangers associated with this treatment.

A healthcare provider will inject methylene blue into a patient's vein through an IV, which can take up to 30 minutes to complete5. The professional will monitor the patient's breathing, blood pressure, kidney function, oxygen levels, and other vital signs during the treatment. The patient will also receive regular blood tests to determine whether the medication reduces methemoglobin levels in their bloodstream.

What Happens After Treatment?

Some patients might only require one dose of methylene blue; others will need additional treatments. Healthcare providers can give patients a second dose of methylene blue an hour after the first one.

Common side effects of this treatment include changes in urine and stool color5. Patients might also experience short-term blurred vision and impaired thinking and reactions. For the first 24 hours after treatment, patients should avoid exposure to sunlight or tanning beds. Methylene blue can make someone more susceptible to sunburn.

Final Takeaways

• Methylene blue is a treatment used in hospital settings for the rare blood disorder methemoglobinemia.
• Methemoglobinemia can reduce the amount of oxygen delivered to the body's tissues and cause symptoms such as fatigue, headache, nausea, vomiting, shortness of breath, and blue-colored skin.
• Glucose-6-phosphate dehydrogenase (G6PD) deficiency
• Healthcare providers might inject methylene blue into a patient's vein via an IV. This can cause the body's metabolism to break down the medication into leukomethylene blue—a reducing agent that lowers methemoglobin levels in the bloodstream.
• Research shows that methylene blue is safe in small doses of <2mg/kg.